Frailty Indices based on the CLSA
We developed five frailty indices (FI) that can be used by researchers who have access to data from the Canadian Longitudinal Study on Aging (CLSA). One FI uses data from the pooled cohort (the Comprehensive and Tracking cohorts combined; FI-52). One uses data from the Tracking cohort (FI-66). The remaining three use the Comprehensive cohort (FI-Self Report, FI-Blood, FI-Examination).
We also developed a standard frailty index based on the CLSA measures (FI-62) that can be used by health care professionals to measure frailty in their patients, by researchers who will collect their own frailty data, or by members of the public who want to calculate their own FI score.
FIs for researchers with access to CLSA:
Using standard methodology, we created a 52-item frailty index (FI-52) using baseline data from CLSA collected in the pooled tracking and comprehensive cohorts between 2011 and 2015 (Pérez-Zepeda et al., 2021).
The items that comprise the CLSA FI-52 reference self-rated health, chronic conditions, activities of daily living, instrumental activities of daily living, cognitive function, and mental health. The proportion of health problems present in a given individual was used to estimate their frailty index score.
Researchers who have access to CLSA data and who would like to replicate the CLSA FI-52 can use our syntax. Note that this syntax is formatted for STATA 16.0 and will work using only the baseline pooled cohort data.
Using weighted frailty index scores and the participants’ age and sex, researchers can use our syntax to calculate normative data for frailty in Canadian males and females over the age of 45. Our work used the first sampling weights provided by CLSA (2017), but can be adapted to newer versions of sampling weights (e.g. 2020).
Using the same methodology as the pooled cohort, we created a 66-item frailty index (FI-66) for the CLSA tracking cohort. The CLSA FI-66 includes the same items as the FI-52 plus an additional 13 mobility items and 1 weight loss item that were only collected in the tracking cohort (i.e. these items are not collected in the comprehensive cohort).
Researchers who have access to CLSA data may replicate this FI using our syntax. They can also use a separate syntax to create normative frailty index data for males and females over the age of 45.
We have developed (Blodgett et al., in press) three additional FIs for the CLSA comprehensive cohort:
1) The CLSA FI-Self Report – This FI was adapted from the CLSA FI-52 constructed for use with the pooled cohort. It consists of 48 self-reported items. Four cognitive scores from the CLSA FI-52 (see pooled cohort above) were excluded.
2) The CLSA FI-Blood – This FI consists of 23 biomarkers from chemistry and hematological reports.
3) The CLSA FI-Examination – This FI consists of 47 items across six domains, including: physical performance, cognition, cardiac, anthropometric, spirometry, and hearing and vision. Due to the lack of clinical reference ranges and the informative variability in performance across most assessments, normative coding of many items was used.
FI for researchers, health care professionals, or members of the public:
We have developed a questionnaire for measuring an individual’s frailty index score using 62 items (CLSA FI-62). This is based on the CLSA FI-66 described above (see tracking cohort above) but excludes four cognitive tests that could not be converted to questionnaire form. Please note that all of our CLSA FIs combine five arthritis-related questions into two FI items. For this reason, our questionnaire includes 62 FI items derived from 65 questions.
The questionnaire can be administered by researchers or health care professionals – or self-administered – to identify an individual’s frailty level. A printable version of the questionnaire is available with an accompanying scoring sheet. This allows users to calculate the frailty index score by hand; the resulting score can be compared to the normative frailty data of Canadians of the same age and sex available using this table. We have also created an online tool that automatically generates a frailty index score upon completion of the questionnaire.
Disclaimer: This tool is meant for education and research purposes only and should not be used for diagnosis or care planning, except under the direction of a health care provider.
Pérez-Zepeda MU, Godin J, Armstrong JJ, Andrew MK, Mitnitski A, Kirkland S, Rockwood K, Theou O. Frailty among middle-aged and older Canadians: Population norms for the frailty index using the Canadian Longitudinal Study on Aging. Age Ageing. 2021; 50(2): 447-456.
Blodgett JM, Pérez-Zepeda MU, Godin J, Kehler DS, Andrew MK, Kirkland S, Rockwood K, Theou O. Frailty indices based on self-report, blood-based biomarkers and examination-based data in the Canadian Longitudinal Study on Aging. Age and Ageing. (Accepted January 3, 2022).